(John Kemp is a Reuters market analyst. The views expressed are his own. Refiles to correct UKERC name in paragraph 1)

By John Kemp

LONDON, July 18 (Reuters) - Most people in Britain want to reduce reliance on fossil fuels, but due more to fears of shortages and rising prices than to fears about climate change, according to a poll developed by researchers at Cardiff University and funded by the UK Energy Research Centre.

Nearly 2,500 people were surveyed across England, Scotland and Wales in August 2012. The results, published on Tuesday in a report on "Transforming the UK energy system: public values, attitudes and acceptability," provide a trove of information about public opinion on climate and energy policy.

By a large majority, respondents were either very concerned (24 percent) or fairly concerned (50 percent) about climate change and thought it was partly (48 percent) or mainly (28 percent) caused by human activity.

Only a minority thought fears about climate change have been exaggerated (30 percent), though more expressed uncertainty about what the effects will really be (59 percent).

Nearly everyone agreed with the statement that Britain needs "to radically change how we produce and use energy by 2050".

Yet when asked about their concerns, affordability and energy security consistently came to the fore as the most important issue.

FEARS ABOUT PEAK OIL LIVE ON

Keeping bills affordable was the most important single priority for respondents (40 percent) followed by making sure the United Kingdom has enough energy to prevent blackouts and fuel shortages (32 percent). Tackling climate change came a distant third (27 percent).

Turning the question on its head, climate change was the least important priority for almost half of the respondents (48 percent).

By overwhelming majorities, those polled were fairly or very concerned gas and electricity would become unaffordable (83 percent); Britain will become too dependent on energy from other countries (83 percent); the country will have no alternatives if fossil fuels are no longer available (83 percent); and petrol will become unaffordable (78 percent).

Nearly four out of five respondents agreed the country should reduce its reliance on fossil fuels (79 percent).

When asked for their reasons, respondents cited concerns about fossil fuels running out, being unsustainable or non-renewable (48 percent), costly (7 percent) and implied dependence on other countries (5 percent), compared with worries they are harmful to the environment and polluting (19 percent) or contribute to climate change (17 percent).

While energy analysts are no longer concerned that oil and gas supplies will peak and start to run out, owing to the shale revolution, these fears continue to resonate strongly with ordinary members of the public.

The same focus on affordability, reliability and convenience comes through in some of the survey's more detailed questions.

Most people are prepared to reduce their own energy use (81 percent) in many cases greatly (58 percent).

Britain's government and climate campaigners are pushing for wider use of electricity, as renewable power generation grows, for home heating, cooking and vehicles to help reduce carbon emissions.

But the poll found fairly modest levels of support for that shift. If electric heating, cooking and vehicles were to become as convenient to use as conventional counterparts, willingness to use them would then climb significantly, especially if they were cheaper.

SAVING THE CLIMATE, CHEAPLY

Cost is clearly central in discussions about energy and climate change, though the study's authors tend to downplay its importance.

To the extent fossil fuels are seen as expensive and unreliable, consumers are keen to reduce their use of them in favour of cleaner, cheaper and more secure sources of energy, which has important environmental benefits, even if this is not the main objective of the shift.

To the extent that clean energy is seen as more expensive, consumers are more hesitant about its benefits and focused on worries about affordability and rising bills.

Neither the survey nor the accompanying focus-group work asked people how much extra they would be prepared to pay or to reduce their energy consumption to avert climate change, owing to the lack of agreement about future commodity, carbon and clean energy prices, among other issues.

But the survey's other findings suggest the answer may be: not much.

Consumers are already very worried about the impact of rising gas and power bills as well as the escalating cost of travelling by road and rail.

In principle they may be willing to pay a bit more to avert climate change, but that "bit more" may turn out to be fairly limited in practice.

The survey contains important implications for fossil-fuel producers as well as environmental campaigners and clean energy companies.

For fossil-fuel suppliers, there is no future unless further price rises can be avoided.

Fossil fuels have already been tarred with a reputation for being dirty and polluting. If they are also seen as expensive and unreliable, the public will want to replace them with wind, solar and hydropower, which are less vulnerable to political disruption and to violent price swings, and make everyone feel good at the same time.

For environmental campaigners and supporters of clean tech, the survey points to unease about rising costs and concerns that energy must be affordable and convenient as well as clean.

There is limited appetite for sacrificing personal comfort and convenience to save the planet.

"Transforming the UK Energy System: Public Values, Attitudes and Acceptability" is available at: http://www.ukerc.ac.uk/support/article3045 (editing by Jane Baird)